The long term of the proposed research is to develop a dental radiography capable of reproducing a desired imaging geometry. The goals of the proposed research are to develop a prototype system and to test it on dry skulls. The patented robot control system (U.S. Patent #5, 113, 424) is capable of reproducing imagery geometry by sensing the 3-D position of the head using an electromagnetic sensor. A known X-ray source to tooth imaging geometry allows it to reposition the source in real-time to achieve this desired imaging geometry. In this way the imaging geometry can be reproduced without mechanical connection of the patient to the X-ray system. The advantage of such a system is the ability to produce radiographs of the entire mouth with a standardized imaging geometry that can used alone or for subtraction radiography to detect subtle change in the dentition. A system such as this can eventually be in place in a clinician's office. The goal of the proposed research is to demonstrate the feasibility of a prototype robot's controlled X-ray system. There are 2 specific aims. First, to develop a robot-controlled X-ray arm; second, to conduct trials with dry skulls, to determine if standardized films created with this system are a more accurate diagnostic tool. To achieve the first goal, an X-ray system will be modified and a study conducted to determine how accurately the arm can be repositioned. To achieve the second goal, radiographs will be taken on dry skulls. In this trial the robot control system will be compared to a subtraction system using occlusal stents. The anticipated outcome is that the robot control system will produce more diagnostically meaningful radiographs and subtraction images.